Avibactam sodium (NXL-104) dihydrate inhibits CTX-M-15 and β-lactamase TEM-1 with IC50 values of 5 nM and 8 nM, respectively, and is a reversible covalent inhibitor of non-β-lactam β-lactamase [1].

Avibactam, a molecule with minimal antibacterial activity, selectively inhibits class A and C β-lactamases, excluding metallo types and Acinetobacter OXA carbapenemases [2]. When combined with ceftazidime (0-256 mg/L), this compound effectively halts the growth of 16 bla KPC-2 positive and 1 bla OXA-232 positive Klebsiella pneumonia strains, exhibiting minimum inhibitory concentrations (MIC) of 50 and 90 for both at 8 mg/L [4].

Ceftazidime-Avibactam, administered at a dosage of 0.375 mg/g subcutaneously every 8 hours for 10 days, exhibited significant therapeutic efficacy against K. pneumoniae strain Y8 infections in a mouse model, as evidenced by enhanced survival and reduced bacterial counts in the spleen and liver. Additionally, a single dose of Avibactam (64 mg/kg; s.c.) demonstrated a mean estimated half-life of 0.24 hours in the plasma of neutropenic mice with Pseudomonas aeruginosa lung infections. In a specific study, six-week-old female BALB/c mice infected with K. pneumoniae strain Y8 were treated with this combination. Results showed a 70% mortality rate in the infected group within four days, while all mice in the PBS control group died within 13 days. Conversely, mice treated with Ceftazidime-Avibactam survived the entire 10-day treatment period, with a 100% mortality rate observed within four days post-treatment cessation. This highlights the compound's ability to significantly reduce bacterial load, offering a potentially effective treatment option for these infections.